This invention relates to a roll film cartridge which is made of plastic material and comprises a shell having an exit slot and end covers mounted at the ends of said shell. Such roll film cartridge is known from Opened German Specification No. 26 12 352 and comprises a shell which at each end facing an end cover is formed with a rib, which is receivable in a groove of the end cover to form a labyrinth gland. Adjacent to the exit slot, the groove is interrupted by a spacer for the exit slot. That edge of the cover which defines the groove on the outside thereof is lower than the rib of the shell. It is apparent that the known roll film cartridge consists of two parts, namely, the shell and the two end covers, which are adapted to be mounted on the ends of the shell.
Roll film cartridges which consist of two parts and are made from sheet metal or plastic material are known too. In both cases the exit slot of the cartridge must be lined with velvet in order to ensure the necessary lighttightness. The application of the velvet ribbon requires an additional operation. The application of a velvet ribbon in order to ensure the required lighttightness involves the further disadvantage that the velvet retains particles of dust, which may scratch the image area of the film. Finally, these known roll film cartridges involve the problem that, the narrower the exit slot of the cartridge the better is its lighttightness. But cartridges having tighter exit slots involve also a higher tension of the film.
Other known cartridges are lighttight without requiring velvet because the film is guided in a curved passage from the roll to the outside of the cartridge. These velvet-free cartridges have not been successful on the market because particularly when they were made of sheet metal it was difficult to avoid excessive costs in providing a film passage having the close tolerances which are required. In a known velvet-free cartridge of plastic, an additional core which defines the film passage is required and also adds to the manufacturing costs. All velvetless cartridges render the loading of film into the cartridges much more difficult so that they are not suitable for commercial use. Such cartridges have had a limited market only as so-called re-loadable cartridges for use by amateurs.
It is an object of the invention so to improve the known roll film cartridge of plastic material that it can be made in a simpler manner and preferably in one piece.